Manufacture of dyestuff intermediates



subject of the Kin Ireland,

srrss JOHN moms, or camsnn, ENGLAND, ASSIGNOR re scerrrsnv urns, no, or

. OABLISLE,

ENGLAND.

I mnurncrunn or nras'rurr mrnnmnnmrns.

Ho Drawing. I

To all whom it may concern.

Be it known 1 that I, JOHN THOMAS, a

of Great Britain and and resi 'ng at Murrell Hill Works, Garlisle, in .the count of Cumbelv land, England,.---have invente certain new andfuseful- Improvements in and Relating to the Manufacture of Dyestufi Intermediates, of which the following is a specifica-' tion.

. This invention relates to the manufacture of intermediates for the production of dyestufl's and more particularly to the manufacture of 1-chlor-Q-methyl-anthraquinone from 2-methyl-anthraquinone in such a way as to enablea complete process for the manufacture of anthraquinone-l-chlor-2-carboxylic acid to be obtained using 2-methyl-anthraquinone as the starting material.

The key. to the invention is the treatment of 2-methyl-anthraquinone in concentrated sulphuric acid (this term in this specifica: .tion or claims including weak oleum) with chlorine, the resulting solution being such that it may be directly submitted, that is to say, without isolation of intermediate bodies, tothe action of a suitable oxidizing agent forthe formation of anthraquinone-l-chlor- .2-carboxylic acid and in those cases where the 2-methyl-anthraquinone is prepared b condensing para-toluoyl-benzoic acid wit sulphuricacld or weak ol'eum this solution may be' directly chlorinated so that a complete process for producing anthraquinone 1'-chlor-2-carboxylic acid from ara-toluoyl benzoic acid is provided. Tl e invention will be mainly described with reference to the comple process for the production of an-thraquino e 1 chlor 2 carboxylic acid from para-toluoyl-benzoic acid.

In carrying the. invention into effect in one form b way of example, 35 parts of par'a-toluoy -bcnzoic acid are treated with 350 parts of weak oleumcontaining 5 per cent of free SO,- in the usual way so as to form 2-methyl-anthraquinone; 0.35 parts of iodine are added and the melt may then be submitted to the action of dry chlorine, for examplefat about 50-60 (3., or preferably an -;analysis is made and suflicient oleum added tobring the strength up to 3'per-cent of free S0,. The chlorination proceeds distinctly more rapidl in solutions containing free SO than in phuric acid. Chlorine 1s i until the -."z-.-.'- in Application mea August a, 192s. Serial No. 955,548.

weight is obtained, after making due allowance for the solubility of chlorine in weak oleum.

Samples may be time to time and the melting point determined. When the melting pointhas dropped below 150, 0., chlorination is proceeded with cautiously and determinations of the percentage of chlorine are taken. When the chlorine content is,13.8 to 14 per cent chlorination is stopped. The melting point at this stage is usually about 14:0 to 149 C. If it is desired'to obtain 1-chlor-2- methyl-anthraquinone the melt at this point may be worked up.

also withdrawn from' The melt is then cooled and to it is added another 350 parts of sulphuric'acid. It is thendiluted by the addition oj water until the strength of the acid is 8O per cent. This causes some. of the 1-chlor-2-methy1-anthraquinone to be precipitated out. To this is then added 95 parts of finely powdered ioxide and the temperature is manganese allowedto rise to about 110 C. and kept at this forsome hours. When oxidation is complete the melt is run down to water and should there. be any unchanged manganese dioxide present, this is removed by adding some bisulphite and boiling. On cooling, the

solution is filtered and the crude anthra-- uinone-l-chlor-2-carboxylic' acid isolated.

fter purification, the yield is about 30 to 32 parts of the required acid. p

The chlorination can be carried out in iron towers.

The chlorinations can be carried out at temperatures different from those given above, thebest conditions being used for the particular body required.

Theproportions of iodine used can also be varied.

The following example illustrates a modifiedprocess according to the present invention Thelproduction of anthraquinone-l-chlor- Q-carboxylic acid from para-toluoyl-benzoic acid may be conveniently carried out as fol- 'lows:-- v

A jacketed stirrer pan is charged with 733 lbs. of 5 per cent oleum and to this is added 77 lbs. of powdered para-toluoyl-benzoic acid. The pan is then closed and the temperature raised to 90 C. during one hour. It is kept at this temperature for one hour and then raised to C. and kept at 100 C. for two hours, the contents being well stirred the whole time.

Cooling water is then turned on to the jacket of the an and 170 lbs. of 20 per cent oleum are ad ed. After-a thorough mixing a sample is taken and the percentage of free SO estimated. This is generally between 3 and 5 per cent and chlorination is commenced. Steamis turned on to thejacket and the temperature' of the'contents of the pan ra'med to 70 C. and the charge is circulated through a tower acked with iron borings, earthenware or ot er suitable material.

temperature is raised to 90 C. and kept at 90. When all the water is in 20.9 lbs. of powdered manganese dioxide is added over a period of 6 hours, the temperature being ke tbetween 90 and 100 C. The mixture is pt for a further four hours at 100 C.

The contents of the pan are then drowned .in 600 gallons 'of cold water and 33 lbs. of sodium bisulphite solution added and the whole boiled until the colour of the contents is a bright yellow. The suspension is then cooled to 30. 0.. further diluted with cold sired this product is obtained by blowing the contents of the pan after chlorination is complete into water and isolating by filtration and washing in the usual'way.

If desirable or more convenient 2-methylanthraquinone from other sources can be used and subjected to chlorination by dissolving it in 10 to 12 times its weight of 5 per cent oleum and then proceeding as outlined above.

Having now described my invention what I claim as new and desire to secure by Letters Patent is 1. The process which consists in chlorination of Q-methyI-anthraquinone and direct oxidation of the product of the aforesaid chlorination all while dissolved in strong sulphuric acid with no isolation of intermediate products.

2. The process which consists in the condensation of para-toluoyl-benzoic acid in a suflicient excess of concentrated sulphuric acid so that sulphuric acid remains in the product, chlorination of the solution thus obtained, and oxidation of the resulting product, with no isolation of intermediate bodies.

In testimony whereof I have signed my name to-this specification.

JOHN THOMAS. 

